Low direct current voltage regulating circuit



@Qin @59 @4% n @D ,/JF'* H. J. LHNDENPJVHU@ @1 L11@ LOW DIUBGT CURRENT VOLTAGE REGULATNG CERCUIT Filed April 25, 1945 Patented Oct. 26, 1948 LOW DIRECT CURRENT VOLTAGE REGULATING CIRCUIT Hendrik Jan Lindenhovius, Eindhoven, Netherlands, assignor, by mesne assignments, to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application April 26, 1946, Serial No. 665,302 In the Netherlands October 17, 1942 Section 1, Public Law 690, August 8, 1946 Patent expires October 17, 1962 Claims.l (Cl. 323-22) The invention relates to a circuit-arrangement for keeping constant the terminal voltages oi.' a consuming apparatus supplied by direct current with the aid of a grid-controlled regulating tube connected in series with a consuming apparatus and of an amplifying tube which serves to amplify the control voltages to be supplied to the control grid of the regulating tube.

In order to ensure that the high operating voltages required for the amplifying tube, such as the anode voltage and the screen grid voltage, are independent of fluctuations of the supply voltage of the circuit-arrangement, it is known to derive them from the voltage which occurs between the output terminals of the circuit-arrangement and which is regulated by the regulatlng tube.

This circuit-arrangement has the drawback that now the voltage on theconsumlng apparatus must have a value which at least corresponds to the lowest anode voltage which is admissible for the amplifying tube, which voltage therefore may be in practice not less than about 40 Volts.

According to the invention, in a circuit-arrangement of the above-described type wherein the anode voltage of the amplifying tube is derived from the regulated voltage, this drawback is eliminated by supplying the regulated voltage to the consuming apparatus through a resistance of constant voltage drop which preferably consists of a glow-discharge tube.

Now the voltage on the consuming apparatus may be taken as low as desired without the potential difference between the anode and the cathode of the amplifying tube becoming too small since this difference at least corresponds to the operating voltage of the glow-discharge tube diminished by the potential difference between the cathode and the control grid of the regulating tube.

In order to be able to earth the negative supply lead of the circuit-arrangement as well as the negative connecting terminal of the consuming apparatus, the resistance of constant voltage drop is preferably included in the positive supply lead of the circuit-arrangement.

The invention will be explained more fully with reference to the accompanying drawing which represents, by way of example, oneem bodiment thereof.

In the form of construction represented I denotes a. consuming apparatus which has to be supplied with a constant direct-current voltage of low value from a source of voltage 2 which fur- 2 nishes a direct-current voltage of varying value and which may consist, for example, of a rectie; system which is to be connected to a power network.

For keeping constant the voltage supplied to the consuming apparatus there is provided between the source of voltage 2 and the consuming apparatus I a circuit-arrangement which comprises input terminals 3, output terminals 4, a triode 6 which is utilized as a regulating tube and which is included in the positive supply lead 5, and an amplifying tube which is represented as a pentode and which serves to amplify the control voltages to be supplied to thev triode. The cathode of the amplifying tube l is connected to the negative supply lead 8 whereas the anode is connected to the cathode of the triode through an anode resistance 9, the screen grid being directly connected to the said cathode. The anode voltage of the amplifying tube 1 is consequently formed by the voltage which occurs between the control grid of the triode 6 and the negative supply lead 8 and which is regulated by the triode.

In order to avoid that in the case of a low voltage on the consuming apparatus the anode voltage and the screen grid voltage of the ampli fying tube 1 acquire inadmissibly low values, the voltage occurring between the cathode of the triode and the negative supply lead is not supplied, directly to the consuming apparatus, as is usual in circuit-arrangements of the type under consideration, but is supplied to the series-connection of the consuming apparatus and a resistance of constant voltage drop which is constituted by a glow-discharge tube l0. In order to obtain the possibility of earthing the negative supply lead 8 and the negative terminal of the consuming apparatus l, the said resistance is included in the positive supply lead 5.

The conti-ol voltages to be supplied to the control grid of the amplifying tube may be obtained in different ways known in themselves, which, if desired, may be utilized simultaneously, according to the desired regulating effect. Thus, for example, in order to obtain forward regulation the control voltages may be derived from the variations of the supply voltage supplied to the input terminals 3 or again, in order to obtain a regulation dependent upon the supply current, from a resistance connected in the negative supply lead. Besides,'in order to obtain backward regulation the control voltages may be derived from the voltage fluctuations occurring on the consuming apparatus.

In the latter case, the control grid of the amplifying tube l is preferably connected in the above-mentioned manner, through a bias voltage battery i i, to the junction point of the resistance of constant voltage drop and the consuming apparatus.

The invention may be applied with particular advantage to circuit-arrangements of the represented type wherein the voltage on the consuming apparatus should be regulable to a very low value, which, as is known in itself, may be effected by regulating the bias voltage of the control grid of the amplifying tube l, For this purpose, for example, the voltage of the battery il may be regulable, as is indicated in the drawing by an arrow, or again the control grid may be connected to an adjustable tap on a resistance connected in parallel with the consuming apparatus. If desired, the glow-discharge tube l may be bridged with the aid of a short-circuiting switch i2 in order to obtain a high voltage on the consuming apparatus.

It is noted, that the invention may, of course, also be advantageously carried into eiect if for the amplication of the control voltage there constant voltage drop characteristic linterposed between said device and said load, an amplifier including an 'electron discharge tube having a control grid, said tube being connected between one terminal of said source and the junction of said device and said resistance, means for applying a voltage proportional 'to the voltage across said load to the control grid of said tube, and means to impress the resultan-t output voltage of said ampliiier on the control electrode of said device yto regulate the voltage supplied to said load.

2. Apparatus for supplying a constant voltage to a load comprising a direct-current source subject to fluctuations and connected to said load. an electron discharge device having a control electrode, said device being connected in series with said source and said load, a glow discharge device interposed between said electron discharge device and said load, an amplifier including an electron discharge -tube having -a control grid, said tube being connected between one terminal of vsaid source and the junction of said devices, means for applying a voltage proportional to the voltage across said load .to the control grid of said tube, and means to impress the resultant output voltage of said amplifier on said control electrode to regulate the voltage supplied to said load.

3. Apparatus for supplying a constant voltage to a load comprising a direct-current source subject to fluctuations and connected to said load, an electron discharge device having a cathode, a control electrode and an anode, a glow discharge device, said devices being serially connected between the positive lead of said source and said load, an amplifier including an electron discharge tube having a cathode. a control grid and an anode, the cathode of said -tube being connected to the negative lead of said source and the anode of said tube being connected to the junction of said serially connected devices, means for applying a voltage proportional to the vol-tage across said load to the control grid of said tube, and means to impress the resultant output voltage of said amplifier on said control elec-trede to regulate the voltage supplied to said load.

4. Apparatus for supplying a constant voltage to a load comprising a direct-current source subject to iiuctuations and connected across said load,

. an elec-tron discharge device having a cathode, a

con-trol electrode and an anode, a glow discharge device interposed in series with said electron discharge device between the positive lead of said source and -said load, the anode of said electron discharge device being connected to said posi-tive lead and the cathode of said electron discharge device being connected via said glow discharge device to one end of said load, an electron discha-nge tube having a cathode, a control grid and an anode, an anode resistor for said tube, the cathode of said tube being connected to the negative lead of said source, the anode of said tube being connected -to the control electrode of said electron discharge device and via said resistor to the cathode of said electron discharge device, and means for applying a voltage proportional to the voltage across said load to the control grid of said tube.

v5. Apparatus for supplying a constant voltage to a load comprising a direct current source subject to uctuaticns and connected across said load, an electron dischargeV device having a cathode, a control electrode and an anode, a glow discharge device interposed in series with said electrron discharge device between ythe positive lead of said source and said load, the anode of said electron discharge device being connected to said positive lead and the cathode of said electron discharge device being connected via said glow discharge device to one end of said load, an electron discharge tube having a cathode, a control grid and an anode, an anode resistor for said tube, lthe cathode of said tube being connected to the negative terminal of said source, the anode of said tube being connected to the control electrode of said electron discharge device and via said resistor to the cathode of said electron discharge device,

and an adjustable source of bias potential connected between the control grid of said tube and the junction of said load and said glow discharge device.

HENDRIK JAN LINDENHOVIUS.

REFERENCES CIITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

